CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues
Revenues	$ 60,492	$ 49,162	$ 111,401	$ 90,836
Cost of revenues
Labor and other operating expenses	38,538	27,200	69,797	51,793
Depreciation, depletion and amortization	5,473	5,167	10,656	10,443
Total cost of revenues	44,011	32,367	80,453	62,236
Gross profit	16,481	16,795	30,948	28,600
Selling, general and administrative expenses	3,848	2,957	7,483	6,024
Operating profit	12,633	13,838	23,465	22,576
Other expense (income)
Interest expense	63	62	126	124
Interest and other income, net	(177)	(91)	(237)	(125)
Total other expense (income)	(114)	(29)	(111)	(1)
Income before income tax expense	12,747	13,867	23,576	22,577
Income tax expense	2,509	2,774	4,670	4,453
Net income	$ 10,238	$ 11,093	$ 18,906	$ 18,124
Net income per share of common stock
Basic (in dollars per share)	$ 1.80	$ 1.96	$ 3.33	$ 3.21
Diluted (in dollars per share)	$ 1.80	$ 1.96	$ 3.33	$ 3.20